Modified poly(ethylene oxide), method of making same and articles using same

ABSTRACT

A method for making modified poly(ethylene oxide) by graft polymerizing thereto organic monomers containing a trialkoxy silane functional group or a moiety that reacts with water to form a silanol group, such as methacryloxypropyl trimethoxy silane, onto the poly(ethylene oxide) is disclosed. The graft polymerization is accomplished by mixing the poly(ethylene oxide), the silane-containing monomer(s) and an initiator and applying heat. Preferably, the method is a reactive-extrusion process. The resulting modified poly(ethylene oxide) has improved water absorption characteristics and melt processabilities and may be used to make thermally processed articles, such as fibers, films and foams, that have improved properties over articles similarly processed from unmodified poly(ethylene oxide).

FIELD OF THE INVENTION

The present invention is directed to a method of modifying poly(ethyleneoxide). More particularly, the present invention is directed to modifiedpoly(ethylene oxide) that crosslinks upon exposure to moisture and isalso melt processable. The present invention also relates to articlesmade from modified poly(ethylene oxide) that are capable of absorbingrelatively large amounts of fluid.

BACKGROUND OF THE INVENTION

Disposable personal care products, such as pantiliners, diapers, tamponsetc., are a great convenience. Such products provide the benefit of onetime, sanitary use and are convenient because they are quick and easy touse. However, disposal of such products is a concern due to limitedlandfill space. Incineration of such products is not desirable becauseof increasing concerns about air quality and the costs and difficultiesassociated with separating such products from other disposed,non-incineratable articles. Consequently, there is a need forbiodegradable personal care products.

Poly(ethylene oxide) (“PEO”) is one of a very few polymers that is bothwater-soluble and thermally processable. PEO has also been shown to bebiodegradable under a variety of conditions. Initial work was done withPEO N-80 (molecular weight˜200,000) which is commercially available fromUnion Carbide. This grade of PEO is suitable for extrusion processinginto film. However, the resultant films have relatively low tensilestrength, low ductility, and brittleness. Typical values are 12 MPabreak stress and elongation at break of 220%. In an unmodified form,high molecular weight PEO is not thermally processable. Melt fractureand excessive vaporization are observed as PEO is extruded. Theresulting resins cannot be cast into thin films and do not haveproperties that are useful for personal care applications.

A key requirement to achieve a substantially biodegradable personal careproduct, such as a diaper is to identify and utilize a biodegradableabsorbent material that provides the expected levels of leakageprotection. There is a wide variety of biodegradable polymers with thepotential to become a functional absorbent, but in the current state ofdevelopment, none provide the leakage protection of sodiumpolyacrylates. However, sodium polyacrylates are not appreciablydegraded in mixed microbial systems unless they are so low in molecularweight (500-700 g/mol) that they are not functional as absorbents.

Consequently, there is a need for biodegradable, absorbent personal careproducts that are made from materials that can be relatively easilyprocessed, such as by thermal processing, so that it can be easilyfabricated into a wide range of structures, such as films, foams, andfibrous webs. Currently available water-soluble resins are not practicalfor melt processing thin films or fibers for personal care applications.What is needed in the art, therefore, is a water soluble resin thatovercomes the difficulties associated with melt processing while alsopossessing good saline absorption characteristics and functional formsmade therefrom are still absorbent, flexible and biodegradable. Examplesof water-soluble resins include poly(alkylene oxides) such as PEO,poly(ethylene glycols), block copolymers of ethylene oxide and propyleneoxide, poly(vinyl alcohol) or poly(alkyl vinyl ethers).

SUMMARY OF THE INVENTION

The present invention is directed to methods for improving salineabsorption characteristics of functional forms made from the silanegraft modified PEO of the present invention while maintaining the meltprocessability of silane graft modified PEO as well as the softness andflexibility of personal care products made therefrom. More particularly,the present invention relates to methods of modifying PEO to improve itssaline absorption characteristics while retaining its meltprocessability by grafting organic monomers containing trialkoxy silanefunctional groups, such as methacryloxypropyl trimethoxy silane, or amoiety that reacts with water to form a silanol group, onto the PEO. Thegrafting is accomplished by combining PEO, silane-containing monomer(s),an initiator and applying heat. In a preferred embodiment, the method ofmodification is a reactive-extrusion process. PEOs modified inaccordance with this invention have improved water absorptioncharacteristics and melt processabilities and can be thermally processedinto films, fibers, foams and other articles which have improvedproperties over films, fibers, foams and articles similarly processedfrom unmodified PEO compositions.

To overcome the disadvantages of the prior art, this invention teaches amethod of grafting trialkoxy silane functional group-containing organicmonomers or monomers containing a moiety that reacts with water to forma silanol group, onto PEO in the melt. Modification of PEO produces apolymer that does not crosslink during melt processing, but rather canbe processed into functional forms, such as fibers, films, foams and thelike. Yet, when these functional forms made from the modified polymer ofthe present invention are exposed or subjected to relatively highmoisture conditions, they crosslink with each other and form a gel thatis capable of absorbing relatively large amounts of saline.Additionally, modified PEO resins in accordance with the presentinvention can be solidified into pellets for later thermal processinginto useful shapes, such as films, fibers, foams and other useful formswhich are in turn useful as components in personal care products. Theresulting personal care products are soft and flexible andbiodegradable.

As used herein, the term “graft copolymer” means a copolymer produced bythe combination of two or more chains of constitutionally orconfigurationally different features, one of which serves as a backbonemain chain, and at least one of which is bonded at some point(s) alongthe backbone and constitutes a side chain. As used herein, the term“grafting” means the forming of a polymer by the bonding of side chainsor species at some point(s) along the backbone of a parent polymer. (SeeSperling, L.H., Introduction to Physical Polymer Science 1986 pp. 44-47which is incorporated by reference herein in its entirety.)

Modification of PEO resins with starting molecular weights of betweenabout 3,350 g/mol and 8,000,000 g/mol are useful in the presentinvention. Modification of PEO resins with starting molecular weights ofbetween about 300,000 g/mol to about 8,000,000 g/mol allows the modifiedPEO resins to be drawn into films with thicknesses of less than about0.5 mil. Modification of PEO resins with starting molecular weights ofbetween about 400,000 g/mol to about 8,000,000 g/mol is preferred forfimmaking. Films drawn from the modified PEO compositions have bettersoftness, flexibility, and greater clarity than films drawn fromunmodified low molecular weight PEO. Thermal processing of films fromhigh molecular weight PEO modified in accordance with this inventionalso results in films with improved mechanical properties over filmssimilarly processed from unmodified low molecular weight PEO films.

Modification of PEO resins with starting molecular weights of betweenabout 50,000 g/mol to about 400,000 g/mol allows the modified PEO resinsto be extruded into fibers using conventional melt spinning processes.Modification of PEO resins with starting molecular weights of betweenabout 50,000 g/mol to about 200,000 g/mol is preferred for fiber making.The modification of PEO in accordance with this invention improves themelt properties of the PEO allowing the modified PEO to be melted andattenuated into fibers. Thus, the modified PEO can be processed intowater-absorbent fibers using both meltblown and spunbond processes whichare useful for liners, cloth-like outer covers, etc. in flushablepersonal products. The modified PEO can be processed intowater-absorbent staple fibers for use in bonded, carded webs or inairlaid structures.

These and other features and advantages of the present invention willbecome apparent after a review of the following detailed description ofthe disclosed embodiments and the appended claims.

DETAILED DESCRIPTION OF THE DISCLOSED EMBODIMENTS

The present invention comprises a grafted PEO that, upon exposure tomoisture, crosslinks into a gel structure capable of absorbingrelatively large amounts of fluids, such as water or saline. Inaccordance with the present invention, PEO is graft polymerized with anorganic moiety capable of graft polymerization with PEO which moietycontains a trialkoxy silane functional group or which moiety reacts withwater to form a silanol group. The silane graft modified PEO resin canbe thermally processed into functional forms, such as films, fibers andfoams. When these functional forms are exposed to moisture, acrosslinking reaction occurs, by the mechanism shown below, to provide agel structure capable of absorbing relatively large amounts of water,such as more than 20 grams of saline per gram of polymer under freeswell conditions.

Water-soluble polymers useful in the present invention include, but arenot limited to, poly(alkylene oxides), such as poly(ethylene oxide)(“PEO”), poly(ethylene glycols), block copolymers of ethylene oxide andpropylene oxide, poly(vinyl alcohol) and poly(alkyl vinyl ethers). Thesewater-soluble polymers must be capable of graft polymerization with anorganic moiety containing a trialkoxy silane functional group or amoiety that reacts with water to form a silanol group. The preferredwater-soluble polymer for use in the present invention is PEO. Theprocess for the graft polymerization of PEO with methacryloxypropyltrialkoxy silane followed by cross-linking upon exposure to moisture isshown below.

Graft Polymerization of PEO with Methacryloxypropyl Trialkoxy Silanefollowed by Exposure to Moisture

Since crosslinking of the silane graft modified PEO does not normallyoccur during thermal processing, the graft modified PEO of the presentinvention provides for more robust thermal processing into functionalforms. Furthermore, since the process of forming the silane graftmodified PEO of the present invention does not require the use ofaqueous solutions, there are no costly and time consuming evaporationsteps involved.

The PEO resins useful for graft modification in accordance with thepresent invention include, but are not limited to, PEO resins havinginitial reported approximate molecular weights ranging from about 10,000g/mol to about 8,000,000 g/mol as determined by rheologicalmeasurements. Such PEO resins are commercially available from, forexample, Union Carbide Corporation having offices in Danbury, Conn., andare sold under the trade designations POLYOX® 205, POLYOX® N-10, POLYOX®N-80, POLYOX® WSR N-750, POLYOX® WSR N-12K and POLYOX® UCARFLOC® Polymer309.

Fibers, films and foams can be made using conventional processingmethods from commercially available PEO resins when modified inaccordance with this invention. The PEO resins useful for modificationfor fiber-making purposes include, but are not limited to, PEO resinshaving initial reported approximate molecular weights ranging from about50,000 g/mol to about 400,000 g/mol. Higher molecular weights aredesired for increased mechanical and physical properties and lowermolecular weights are desired for ease of processing. Desirable PEOresins for fiber making have molecular weights ranging from 50,000 to300,000 g/mol before modification and more desired PEO resins for fibermaking have molecular weights ranging from 50,000 to 200,000 g/molbefore modification. The PEO compositions modified from PEO resinswithin the above resins provide desirable balances between mechanicaland physical properties and processing properties. Three PEO resinswithin the above preferred ranges are commercially available from UnionCarbide Corporation and are sold under the trade designations POLYOX®N-750, POLYOX® WSR N-10 and POLYOX® WSR N-80. These three resins havereported approximate molecular weights, as determined by rheologicalmeasurements, of about 100,000 g/mol to 300,000 g/mol.

Other PEO resins available from, for example, Union Carbide Corporation,within the above approximate molecular weight ranges are sold under thetrade designations WSR N-750, WSR N-3000, WSR-3333, WSR-205, WSR-N-12K,WSR-N-60K, WSR-301, WSR Coagulant, WSR-303. (See POLYOX®: Water SolubleResins, Union Carbide Chemicals & Plastic Company, Inc., 1991 which isincorporated by reference herein in its entirety.) Both PEO powder andpellets of PEO can be used in this invention since the physical form ofPEO does not affect its behavior in the melt state for graftingreactions. This invention has been demonstrated by the use of PEO inpowder form as supplied by Union Carbide. However, the PEO resins to bemodified may be obtained from other suppliers and in other forms, suchas pellets. The PEO resins and modified compositions may optionallycontain various additives, such as, plasticizers, processing aids,rheology modifiers, antioxidants, UV light stabilizers, pigments,colorants, slip additives, antiblock agents, etc., which may be addedbefore or after modification.

Organic monomers capable of graft polymerization with PEO which monomerscontain a trialkoxy silane functional group or a moiety that reacts withwater to form a silanol group are useful in the practice of thisinvention. The trialkoxy silane functional group has the followingstructure:

wherein R₁, R₂ and R₃ are alkyl groups independently having 1 to 6carbon atoms. The term “monomer(s)” as used herein includes monomers,oligomers, polymers, mixtures of monomers, oligomers and/or polymers,and any other reactive chemical species which is capable of covalentbonding with the parent polymer, PEO. Ethylenically unsaturated monomerscontaining a trialkoxy silane functional group are appropriate for thisinvention and are desired. Desired ethylenically unsaturated monomersinclude acrylates and methacrylates. A particularly desirableethylenically unsaturated monomer containing a trialkoxy silanefunctional group is methacryloxypropyl trimethoxy silane.Methacryloxypropyl trimethoxy silane is commercially available from DowCorning, having offices in Midland, Mich., under the trade designationZ-6030 Silane. Other suitable ethylenically unsaturated monomerscontaining a trialkoxy silane functional group include, but are notlimited to, methacryloxyethyl trimethoxy silane, methacryloxypropyltriethoxy silane, methacryloxypropyl tripropoxy silane,acryloxypropylmethyl dimethoxy silane, 3-acryloxypropyl trimethoxysilane, 3-methacryloxypropylmethyl diethoxy silane,3-methacryloxypropylmethyl dimethoxy silane, and 3-methacryloxypropyltris(methoxyethoxy) silane. However, it is contemplated that a widerange of vinyl and acrylic monomers having trialkoxy silane functionalgroups or a moiety that reacts easily with water to form a silanolgroup, such as a chlorosilane or an acetoxysilane, provide the desiredeffects to PEO and are effective monomers for grafting in accordancewith the present invention.

The amount of organic monomer having trialkoxy silane functional groupsor silanol-forming functional groups relative to the amount of PEO mayrange from about 0.1 to about 20 weight percent of monomer to the weightof PEO. Desirably, the amount of monomer should exceed 0.1 weightpercent in order sufficiently to improve the processability of the PEO.A range of grafting levels is demonstrated in the Examples. Typically,the monomer addition levels are between about 1.0% and about 15% of theweight of the base PEO resin; particularly, between about 1.0% and about10% of the weight of the base PEO resin; especially, between about 1.5%and about 5.5% of the weight of the base PEO resin.

A variety of initiators may be useful in the practice of this invention.When grafting is achieved by the application of heat, as in areactive-extrusion process, it is desirable that the initiator generatesfree radicals through the application of heat. Such initiators aregenerally referred to as thermal initiators. For the initiator tofunction as a useful source of radicals for grafting, the initiatorshould be commercially and readily available, stable at ambient orrefrigerated conditions, and generate radicals at reactive-extrusiontemperatures.

Compounds containing an O—O, S—S, or N═N bond may be used as thermalinitiators. Compounds containing O—O bonds; i.e., peroxides, arecommonly used as initiators for graft polymerization. Such commonly usedperoxide initiators include: alkyl, dialkyl, diaryl and arylalkylperoxides such as cumyl peroxide, t-butyl peroxide, di-t-butyl peroxide,dicumyl peroxide, cumyl butyl peroxide, 1,1-di-t-butylperoxy-3,5,5-trimethylcyclohexane,2,5-dimethyl-2,5-di(t-butylperoxy)hexane,2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3 and bis(a-t-butylperoxyisopropylbenzene); acyl peroxides such as acetyl peroxides andbenzoyl peroxides; hydroperoxides such as cumyl hydroperoxide, t-butylhydroperoxide, p-methane hydroperoxide, pinane hydroperoxide and cumenehydroperoxide; peresters or peroxyesters such as t-butyl peroxypivalate,t-butyl peroctoate, t-butyl perbenzoate,2,5-dimethylhexyl-2,5-di(perbenzoate) and t-butyl di(perphthalate);alkylsulfonyl peroxides; dialkyl peroxymonocarbonates; dialkylperoxydicarbonates; diperoxyketals; ketone peroxides such ascyclohexanone peroxide and methyl ethyl ketone peroxide. Additionally,azo compounds such as 2,2′-azobisisobutyronitrile abbreviated as AIBN,2,2′-azobis(2,4-dimethylpentanenitrile) and1,1′-azobis(cyclohexanecarbonitrile) may be used as the initiator. Thisinvention has been demonstrated in the following Examples by the use ofa liquid, organic peroxide initiator available from R. T. VanderbiltCompany, Inc. of Norwalk, Conn., sold under the trade designation VAROXDBPH peroxide which is a free radical initiator and comprises2,5-bis(tert butylperoxy)-2,5-dimethyl hexane along with smaller amountsof di(tert butylperoxide). Other initiators may also be used, such asLUPERSOL® 101 and LUPERSOL® 130 available from Elf Atochem NorthAmerica, Inc. of Philadelphia, Pa.

A variety of reaction vessels may be useful in the practice of thisinvention. The modification of the PEO can be performed in any vessel aslong as the necessary mixing of PEO, the monomer and the initiator isachieved and enough thermal energy is provided to affect grafting.Desirably, such vessels include any suitable mixing device, such asBrabender Plasticorders, Haake extruders, Bandbury mixers, single ormultiple screw extruders, or any other mechanical mixing devices whichcan be used to mix, compound, process or fabricate polymers. In adesired embodiment, the reaction device is a counter-rotating twin-screwextruder, such as a Haake extruder available from Haake, 53 West CenturyRoad, Paramus, N.J. 07652 or a co-rotating, twin-screw extruder, such asa ZSK-30 twin-screw, compounding extruder manufactured by Werner &Pfleiderer Corporation of Ramsey, N.J. It should be noted that a varietyof extruders may be used to modify the PEO in accordance with theinvention provided that mixing and heating occur.

The present invention is further illustrated by the following examples,which are not to be construed in any way as imposing limitations uponthe scope thereof. On the contrary, it is to be clearly understood thatresort may be had to various other embodiments, modifications, andequivalents thereof which, after reading the description herein, maysuggest themselves to those skilled in the art without departing fromthe spirit of the present invention and/or the scope of the appendedclaims.

EXAMPLE 1

Material

Polyethylene oxide (“PEO”), supplied by Union Carbide under the namePOLYOX Water Soluble Resins, was used. POLYOX WSR-205 having a molecularweight of about 600,000 g/mol was used in powder form. The reactivepolar vinyl monomer used was 3-(trimethoxysilyl) propyl methacrylatesupplied by Aldrich Chemical Company and manufactured by Dow Comingunder the trade name, Dow Corning Z-6030 Silane. The peroxide initiatorused was Varox DBPH, supplied by R. T. Vanderbilt Company, Inc.

Chemistry

The monomer is composed of two functional groups. The methacrylatefunction reacts with PEO after a free radical site is initiated withperoxide. The resultant modified PEO resin is still thermallyprocessable as long as it is kept relatively dry. The crosslinking takesplace from the other end of the molecule at the alkoxysilane function.The alkoxysilane is readily hydrolyzed into a more reactive silanol andthe silanol condenses with another silanol to form a cross-linkednetwork. Because the grafting monomer has three alkoxysilanes, eachgraft site is theoretically capable of forming three crosslinks. Use ofthis type of grafting monomer provides a modified resin, which, whilekept relatively dry, can be fabricated into useful structures, and then,when exposed to humid air, become crosslinked. The result is a materialthat retains the versatility of thermal processability into a variety ofstructures along with the capability of using those structures forabsorbency. This unusual combination of features is available becausethe crosslinked, hydrophilic network is generated after the structure isfabricated.

Equipment

A bench-scale HAAKE twin-screw extruder was used. This unit contains aset of custom-made, counter-rotating conical twin screws.

Screw Design for the HAAKE Extruder

A general characteristic description is provided in Table 1 since theexact dimensions may be proprietary to the extruder manufacturer.

TABLE 1 Sections Descriptions Section 1: A double flighted forwardpumping section: Large screw lead (pitch) and a high helix angle Section2: A double flighted forward pumping section: Screw pitch is smallerthan Section 1 Section 3: A double flighted forward pumping section:Screw pitch is smaller than Section 2 Section 4: A double flighted andnotched reversed pumping section One complete flight with notchesSection 5: A double flighted notched forward pumping section Twocomplete flights Section 6: A double flighted forward pumping sectionScrew pitch is between sections 1 and 2.

The die has two openings of 3 mm in diameter, which are separated by 10mm. The strands were cooled in air and subsequently pelletized. The feedsection was not heated, rather it was cooled by water. The extruder hasthree heating sections from the feeding section towards the diedesignated as Zone 1, Zone 2, and Zone 3. The die was designated as Zone4.

Reactive Extrusion Process

The first reactive extrusion was done on a HAAKE twin screw extruder of10/1 L/D with custom designed screws (described above) at a rate of 5pounds per hour. The pelletized POLYOX 205 was metered into the throatof the extruder at a rate of 37.8 g/min with a K-Tron feeder. In thesame manner, Varox DBPH peroxide was metered at a rate equivalent to0.25 weight percent of the POLYOX 205 and the Z-6030 silane was meteredin with an Eldex pump at a rate of 2 to 5 weight percent of the POLYOX205. The temperature profile for the heating zones were 150°, 160°,160°, and 170° C. The screw speed was 150 rpm. The strands were cooledin air using a fan-cooled conveyer belt. The solidified strands of thegrafted POLYOX 205 were then pelletized using a Conair pelletizer.

The sample pellets from this experiment were stored under ambientconditions for four months and then under high humidity (33° C. and 80%relative humidity) for seven days. The resin samples were tested todetermine the ultimate gel fraction according to the procedure describedbelow. The gel fraction is the portion of the sample that iscross-linked and no longer soluble in water. The soluble fraction isequal to 1-(gel fraction).

Gel Fraction Test

A sample of film or resin pellet with a weight of 30 to 50 milligrams isweighed in the dry state to the nearest tenth of a milligram. The testsample is place in a 500 ml bottle to which 100 ml of distilled water isadded. The bottle is shaken on a laboratory shaker for 30 minutes atroom temperature. The contents of the bottle are filtered under vacuumwith a Beuchner funnel using Whatman 55 mm filter paper (catalogue #1001 55) which was pre-dried at 60° C. and weighed to the nearest tenthof a milligram. The insoluble portion of the sample is dried along withthe filter paper at 60° C. for two hours and then weighed to determinethe dry weight of insoluble material.

Gel fraction or percent gel is taken as the dry weight of recovered(insoluble) material divided by the initial dry weight of the sample.Generally, the average of 5 replicates is reported in Table 2 below:

TABLE 2 Extruder Weight % Weight % Pressure Gel Sample Z6030 Varox DBPH(psi) Fraction 1-1 0 0 530 0 1-2 2 0.15 330 0.91 1-3 5 0.25 430 Nottested

The addition of the monomer and peroxide initiator results in areduction in extruder pressure compared to the control. The reducedpressure is indicative of reduced melt viscosity. This result indicatesthat the PEO has been modified into a form that is water-absorbent andnot completely water-soluble like the control resin (sample 1-1).

EXAMPLE 2

The following samples were prepared using the same method and extrudertemperatures as described above in Example 1 and using the proportionsof ingredients indicated in Table 3 below. Since the first sampleresulted in low extruder pressure, the temperatures were reduced tobring the extruder pressure into the proper range.

TABLE 3 Weight % vinyl Weight % Extruder triethoxy Varox pressure Samplesilane DBPH (psi) Comments, Observations 2-1-a 5 .25  92 Very lowpressure, temperatures reduced to 120, 130, 130, 140 2-1-b 5 .25 270 Lowmelt viscosity 2-2 2 .15 350 Slight pressure increase 2-3 0 0 700 P205control, high pressure, rough strands

Pellets from samples 2-1-b, 2-2 and 2-3 were stored for approximatelyten weeks under laboratory conditions, exposed to ambient humidity. Allthree samples aged under these conditions, dissolved in water afterstanding overnight.

The resin samples prepared with triethoxy vinyl silane remainedwater-soluble. This result suggests that this monomer was not graftedonto P205 under the same conditions that were effective for graftingZ6030. The significant reduction in melt pressure and melt viscosityindicates that chain scission of the PEO was occurring rather thangrafting. Different conditions or initiators may be needed to inducegrafting between PEO and triethoxy vinyl silane.

EXAMPLE 3

A third reactive extrusion experiment was conducted to evaluate theeffect of higher addition level of the Z6030 monomer along withproportionately higher addition of the peroxide initiator. The samescrew design and production rate as EXAMPLE 1 was used. The pelletizedPOLYOX 205 was metered into the throat of the extruder at a rate of 37.8g/minute with a K-Tron feeder. Dow Corning Z-6030 Silane was meteredinto the throat of the extruder with an Eldex pump at a rate of 3.78g/minute, equivalent to ten weight percent of the POLYOX 205. In thesame manner, Varox DBPH peroxide was metered at a rate equivalent to0.40 weight percent of the POLYOX 205. A second code was run at fiveweight percent addition of Z6030 with Varox DBPH peroxide metered at arate equivalent to 0.33 weight percent of the POLYOX 205. Thetemperature profile for the heating zones were 150°, 160°, 160°, and170° C. The strands were cooled in air using a fan-cooler conveyor belt.The solidified strands of the grafted POLYOX 205 were then pelletized ona Conair pelletizer.

The sample descriptions and gel fraction results are shown in the Table4 below. These gel fraction results were obtained after six months atambient conditions followed by one week at 80% relative humidity.

TABLE 4 Weight % Weight % Extruder Gel Sample Z6030 Varox DBPH pressure(psi) Fraction 3-1 10 .40 420 .92 3-2  5 .33 450 .95

This result indicates that five percent Z6030 is sufficient monomer toprovide a nearly fully crosslinked, PEO gel.

EXAMPLE 4

The Z6030 reactive grafting was done with a ZSK-30 extruder. A ZSK-30co-rotating, twin-screw extruder (manufactured by Werner & Pfleiderer)with 14 barrel sections and 1338 mm total processing section length wasused. The first barrel was not heated, but cooled by water. The peroxidewas injected into barrel #5 and the Z6030 monomer was injected intobarrel #6. Both chemicals were injected via a pressurized nozzleinjector. The die has four openings of 3 mm in diameter, which areseparated by 7 mm. Polymer strands were extruded onto an air-coolingbelt and subsequently pelletized.

The following extruder barrel temperatures (in ° C.) were set to thefollowing levels during the extrusion as shown in Table 5:

TABLE 5 Zone 1 Zone 2 Zone 3 Zone 4 Zone 5 166° 180° 180° 180° 180°

The polymer melt temperature was 195°-205° C. The polymer strands werecooled on a stainless steel cooling belt and subsequently pelletized.

TABLE 6 ZSK-30 Screw Configuration for Reactive Extrusion Element No.Description  1 PKR 10  2 20/10  3 42/42  4 42/42  5 28/28  6 28/28  720/20  8 20/20  9 KB45/5/28 10 KB45/5/14 11 28/28 12 28/28 13 28/28 1428/28 15 20/20 16 28/28 17 28/28 18 20/20 19 KB45/5/42 20 28/28 21 20/2022 KB45/5/28 23 KB45/5/14 LH 24 28/28 25 20/20 26 20/20 27 28/28 2828/28 29 20/20 30 20/20 31 KB45/5/14 32 KB45/5/14 33 20/20 34 20/20 3520/20 36 28/28 37 28/28 38 28/28 39 20/20 40 20/10 LH 41 42/42 SK 4242/42 SK 43 42/42 44 20/20 45 20/20 46 20/20 47 20/20 48 20/20 49 20/2050 20/20 51 20/20 52 20/20 53 20/10 54 20/10 55 20/10 56 20/10 57 20/1058 20/10 59 20/10 60 14/14

The PEO powder resin was fed into the ZSK-30 extruder with a K-Tronvolumetric feeder at a throughput of 20 lbs/hr. The modified PEO strandswere cooled between stainless steel belts that were cooled with waterfrom the opposite side followed by pelletization.

The results are shown in Table 7 below:

TABLE 7 Weight % Extruder pressure Weight % Varox (psi)/% torque/meltGel Sample Z6030 DBPH temperature° C. Fraction 4-1 5.6 .165 320/46%/214.94 4-2 5.6 .33 320/46%/216 Not tested 4-3 11.3 .33 380/47%/218 Nottested 4-4 11.3 .66 390/48%/216 .96

The variation in monomer and peroxide levels had minimal effect on theprocess data for pressure and torque. Gel fraction for samples 4-1 and4-4 was tested after four months at ambient temperature and humidity andone week at elevated humidity and temperature (33° C. and 89% relativehumidity).

EXAMPLE 5

Another reactive extrusion run on the ZSK-30 was designed to determinethe effect of peroxide initiator addition and screw rpm, whichdetermines residence time for the reaction, upon the resin properties.The silane monomer addition level was held constant at 1.3 mole percent(based on moles of ethylene oxide repeat) or 7.3 weight percent. Thestandard settings for temperature were the same as described in Example4.

The settings for the experimental variables and the process datacollected during the experiment are shown in Table 8, below.

TABLE 8 Variable Settings and Process Data VARIABLE SETTINGS PROCESSRESPONSE DATA Melt Percent of Wt. % Temp maximum Melt Run # Rpm Peroxide(° C.) Torque Pressure 5-1 300 0.22 210 45 600 5-2 100 0.22 200 85 8105-3 100 0.13 200 86 830 5-4 300 0.13 205 42 700 5-5 200 0.17 205 50 8005-6 100 0.13 201 86 890 5-7 300 0.13 206 43 700 5-8 300 0.22 206 42 6005-9 100 0.22 199 85 780

The process data in Table 8 indicates a significant effect of the screwrpm upon the torque. Note that a reduction in rpm from 300 to 100results in the torque readings increasing to nearly double. Asignificant, but less dramatic increase is observed in the melt pressureat the reduced rpm setting. Changes in the peroxide addition level hadminimal effect on torque or pressure within the range studied.

Gel Fraction Results

Gel fraction results 165 hours cure at 33° C. and 80% relative humidityare shown in Table 9 below:

TABLE 9 Weight % Resin Sample rpm Varox DBPH Gel Fraction 5-6 100 0.130.87 5-7 300 0.13 0.82 5-8 300 0.22 0.84 5-9 100 0.22 0.85

EXAMPLE 6

To provide a modified PEO resin suitable for fiber spinning, a lowermolecular weight PEO, POLYOX N-80, was used as the starting resin forreactive grafting on the ZSK-30 extruder. The initial molecular weightof this resin was 200,000 g/mol. Temperature settings for the extruderwere the same as Examples 4 and 5. Other process settings are shown inthe Table 10 below.

TABLE 10 Resin Wt % Wt % Varox Process Data Gel Sample Z6030 DBPH rpmPressure/torque Fraction 6-1 7.3 0.17 200 190/59 0.62

The lower molecular weight PEO results in lower extruder pressurecompared to the POLYOX 205.

In the examples that follow, the modified PEO resin was converted intofilm within one or two days of preparation so that the resin would stillbe in an uncrosslinked state.

For film processing, a Haake counter-rotating, twin-screw extruder wasused with a 4 inch slit die attached. A chilled wind-up roll maintainedat 15°-20° C. was used to collect the film. The temperature profile forthe four heating zones was 170°, 180°, 180° and 190° C. Screw speed andwind-up speed were adjusted such that the film thickness was 2 to 3 mil.The process was allowed to stabilize before the film was collected. Filmsamples were tested for gel fraction according to the test methodpreviously described. In addition, the films were tested for fluidabsorbency (gram per gram uptake) under unrestrained swelling conditionsaccording to the following test method.

Gram per Gram Uptake (Free Swell)

A sample of film or resin pellet with a weight of 30 to 50 milligrams isweighed in the dry state to the nearest tenth of a milligram. The testsample is place in a 500 ml bottle to which 100 ml of distilled water isadded. The bottle is shaken on a laboratory shaker for 30 minutes atroom temperature. The contents of the bottle are filtered under vacuumwith a Beuchner funnel using Whatman 55 mm filter paper. The swollensample is removed from the filter paper and weighed to the nearestmilligram.

Gram per gram uptake is calculated as the wet weight of recovered(insoluble) material, divided by the initial dry weight of the sample,minus 1. Generally, the average of 5 replicates is reported. A similarprocedure is used with 0.9% saline replacing distilled water.

Films from Examples 1 and 2 were conditioned in a high humidityenvironment (80% relative humidity at 33° C.) for 16 hours. Four filmsamples were cut and weighed: 5% silane (dry film), 5% silane (humidityconditioned), 2% silane (dry film), 2% silane (humidity conditioned).The films were place in a vial of 20 ml of 0.9% saline and kept at 35 C.After 16 hours in a free swell condition, the liquid was poured off andthe gel isolated, blotted to remove surface moisture, and weighed. Gramper gram uptake under these conditions is shown in Table 11 below.

TABLE 11 Film Resin Ambient Humidified Sample Source DescriptionCondition Uptake Condition Uptake 7-2 1-2 2% Z6030  3 g/g  9 g/g 7-3 1-35% Z6030 23 g/g 20 g/g 7-4 2-1-b 5% vinyl silane Dissolved Dissolved 7-52-2 2% vinyl silane Dissolved Dissolved

These initial results indicate the high absorbency of modified PEOresins when they are successfully grafted and allowed to crosslink.However, if grafting is not successful, as in samples 7-4 and 7-5, thefilm responds to saline much like unmodified PEO and dissolves.

Uptake Of Simulated Menses

Since PEO crosslinked by other means was previously known to be aneffective absorbent for menses, films from this extrusion experimentwere also tested for absorbency with simulated menses.

Films samples (1.5″×1.5″), prepared from POLYOX 205 grafted with fivepercent Z6030, were soaked in 20 ml of menses simulant composed of swineblood of controlled hemocrit with albumin added to simulate thevisco-elastic properties of menses. The samples were soaked for 30minutes, removed, the excess fluid was drained from the surface, andthen weighed. This weight is used to calculate the saturated uptake. Thesample is then placed under pressure of 0.5 psi and then weighed againto determine the blotted uptake. The results are shown below in Table12:

TABLE 12 Saturated Blotted Sample Uptake (g/g) Uptake (g/g) 5% Z6030,ambient 21 10 (for 2 months) 5% Z6030, humidified 13 10 24 hr.

Thermal Analysis

Table 13 below contains the differential scanning calorimeter (“DSC”)results for the Z6030 grafted POLYOX 205 in comparison to the ungraftedresin. Both the heating and the cooling rates were 20° C. per minute.There are several notable differences in the grafted polymer compared tothe ungrafted P205.

1. There is a significant increase in the crystallization temperature(Tc) for the grafted resins. (˜40° C. for the ungrafted resin comparedto ˜47° C. for the grafted).

2. Based on the second heat cycle (which erases prior heat historyeffects) the grafted resins appear to have a lower melt temperature anda slightly higher glass transition temperature (T_(g)) compared to theunmodified resin.

TABLE 13 Initial Thermal Analysis Results POLYOX Humidi- Humidi- 205(un- 2% fied 5% fied modified) Z6030 Condition Z6030 Condition Filmresin 1-1 1-2 1-2 1-3 1-3 source 1^(st) heat −55.7 −52.2 −54 −55.5 −54.5Tg (C.) Tm (onset/ 60.4/71.3 56.8/62.6 60.6/67.2 56/61.7 58.7/66.1 peak)heat of 126 124 166 139 162 fusion estimated 59% 58% 78% 65% 76%crystallinity (100% = 213 J/g) Tc (onset/   47/39.8 49.3/46     50/47.949.4/47     50/48.7 peak) heat of 114 116 134 130 126 fusion estimated54% 54% 63% 61% 59% crystallinity (100% = 213) 2nd heat Tg −55.6 −46−50.5 2nd heat Tm 60.5/71.3 59.2/64.7 58.6/64.4 58.1/63.9 57.9/63.4(onset/ peak) heat of 122 122 139 136 140 fusion estimated 57% 57% 65%64% 66% crystallinity (100% = 213)

Film Properties

Film properties for the Z6030 grafted POLYOX 205 are shown in Table 14below for both ambient conditions and humidified film. For the sake ofcomparison, the properties of POLYOX 205 grafted with hydroxyethylmethacrylate (“HEMA”) are also shown. In general, the ambient films havesimilar properties to the HEMA grafted film, particularly low modulus,high break stress, and high elongation at break. The most notable changefor films that have been conditioned under high humidity to inducecrosslinking is an increase in the film modulus.

TABLE 14 Film Properties from Initial Extrusion Experiment Film FilmThick- Break % Energy Resin Orien- ness Stress Strain @ Modulus to BreakSource tation (mils) (Mpa) break (Mpa) (J/cc) 1-3 MD 3.18 22.2 1075 103159 1-3 MD 3.13 23.4 1132 146 179 1-2 MD 2.98 14.2  843 162 105 1-2 MD2.96 13.7  592 226  75 205 MD 1.16 25.4 1153 163 174 grafted with 1.5%HEMA

Grafting POLYOX 205 with Z6030 silane provides for a crosslinkablestructure with good absorbency for water, saline, and simulated menses.The excellent dry film properties previously obtained with grafted PEOare retained when Z6030 is used as the grafting monomer. All filmsprepared with triethoxy vinyl silane remained water-soluble.

EXAMPLE 7

Another extrusion experiment was run as a control experiment without theaddition of the peroxide initiator to confirm the graft chemistrydescribed above. Without the peroxide initiator, the resulting materialwould be a blend of PEO and the Z-6030 monomer rather than a graftedcopolymer.

Pelletized POYOX 205 was metered into the throat of the Haake extruderas described above at a rate of 37.8 g/min with a K-Tron feeder.Methacryloxypropyl silane (Dow Corning Z-6030 Silane) was metered intothe throat of the extruder with an Eldex pump at a rate of 3.78 g/min,equivalent to ten weight percent of the POYOX 205. The temperatureprofile for the heating zones was 150°, 160°, 160°, and 170° C. Theresultant strands were cooled in air using a fan-cooler conveyer belt.And the solidified strands of the grafted POLYOX 205 were thenpelletized on a Conair pelletizer. A film was cast with a thickness ofabout 3 mils (0.76 mm).

Gel Fraction

A film sample from this experiment was conditioned at 37° C. and 80%relative humidity for 7 days. Gel fraction testing using the proceduredescribed above resulted in gel content of less than two percent. Incontrast, when the initiator is included to promote grafting of thealkoxysilane onto the PEO, the gel fraction under similar conditioningis typically more than 60 percent even with a shorter time ofhumidification.

EXAMPLE 8

Films were prepared from the modified PEO resins of Example 4 and themechanical properties of the dry film were tested. The MD filmproperties in the dry state are shown in Table 15 below. The changes inproperties that result from the formation of crosslinks under the curingcondition are evident. For this table, the cure condition was 92 hoursat 37° C. and 80% relative humidity.

TABLE 15 Film Properties as a Function of Cure Break stress % Strain @Modulus Energy to (Mpa) break (Mpa) Break (J/cc) Sample Uncross- cross-Uncross- cross- Uncross- cross- Uncross- cross = MD Film Propertieslinked linked linked linked linked linked linked linked Film 8-1 (Resin4-1): 21.8 30.6  942 1127 143 192 136 213  5.6% Z6030  .16% peroxideFilm 8-2 (Resin 4-2): 20.9 25.9 1158 1084 132 177 156 177  5.6% Z6030 .33% peroxide Film 8-3 (Resin 4-3): 19.5 27.7 1034 1105 111 173 132 18811.2% Z6030  .33% peroxide Film 8-4 (Resin 4-4): 19-8 25.3 1052 1008 133190 137 167 11.2% Z6030  .66% peroxide

As the results indicate, crosslinking provides for improved filmproperties. Significant improvements are evident for break stress andenergy to break. An increase in modulus is also evident, but the modulusdoes not increase to levels that are much different from HEMA-graftedPEO, with a modulus of about 165 Mpa. The high strain at break is notnegatively impacted by the crosslinking reaction.

EXAMPLE 9

Films were prepared from the modified PEO resins of Example 5.

Gel fraction results after 26 and 165 hours at 33° C. and 89% relativehumidity are shown in Table 16 below, along with results forgram-per-gram uptake of 0.9% saline.

TABLE 16 Wt. % 26 hour 165 hour 165 hour Resin Perox- gel gel g/g FilmSource RPM ide fraction fraction uptake 9-1 5-1 300 .22 40 68 19.4 9-25-8 300 .22 18 58 16.9 9-3 5-2 100 .22 68 74 17.6 9-4 5-9 100 .22 57 8014.2 9-5 5-4 300 .13 Not 50 22.2 tested 9-6 5-7 300 .13 14 65 21.2 9-75-3 100 .13 77 83 19.3 9-8 5-6 100 .13 81 75 14.8 9-9 5-5 200 .17 79 8413.7

The results indicate a significant effect of screw rpm and a minimaleffect of peroxide level. Note that low screw rpm, which results in alonger residence time, produces a greater gel fraction, presumably as aresult of higher grafting.

In general, the data from the extended cure time follows the samepattern observed after 26 hours of cure. The screw rpm (residence time)had the largest impact, while the peroxide level had little effect. Notethat there is an overall increase in the gel fraction with theadditional cure time.

The results for g/g uptake suggest that the capacity of the crosslinkedPEO is increased with a lower level of crosslinking. This inverserelationship between capacity and crosslink concentration is consistentwith the trends observed with polyacrylate super absorbents and alsowith PEO crosslinked with urethanes. The results also suggest that lowerlevels of the Z6030 crosslinking monomer under reactive graftingconditions that promote high grafting efficiency could provide forhigher capacity at a lower cost. Therefore, for certain applications itis desirable that the polymer have a level of gel formation of about2%-3% by weight; desirably, at least about 2% by weight. Such low levelsof crosslinking may also be used to produce a polymer that has delayedwater solubility or dissolution.

However, this uptake data is obtained under free swell conditions. Forabsorbency under load (AUL), a higher crosslink density may be needed.Therefore, for other applications it is desirable that the polymer havea level of gel formation of up to about 98% by weight. For otherapplications, it may be desirable to have a level of gel formation ofabout 50%-60% by weight.

An even more ideal structure would be similar to the shell crosslinkedpolyacrylates. This gradient in crosslinking might be achieved bysurface application of a catalyst for the crosslinking reaction. Such aproduct would have a higher degree of crosslinking on the surface and alower degree of crosslinking in the interior. Therefore, for certainapplications it is desirable to have a level of gel formation of about2% to about 60% by weight, and for other applications a level of gelformation of about 50% to about 98% by weight. The ability to vary theamount of gel formation provides the ability to select the propertiesthat are desired in the final product.

EXAMPLE 10

Gel Fraction Under Ambient Aging Conditions

Film samples were stored in plastic bags under ambient laboratoryconditions of temperature and the humidity available within the plasticbag. These conditions simulate the exposure conditions for filmsfabricated into a component of a personal care product that is packagedin a plastic bag. As shown in Table 17 below, the alkoxysilane graftedPEO crosslinks slowly under these storage conditions.

TABLE 17 Resin Storage Gel Sample Description Source Time Fraction  5%Z6030  .33% peroxide 3-2  4 weeks 32%  5% Z6030 0.25% peroxide 1-3  8weeks 52%  5% Z6030  .33% peroxide 3-2 18 weeks 69% 10% Z6030  .40%peroxide 3-1 18 weeks 70%

EXAMPLE 11

Addition of Catalyst to Accelerate Crosslinking Reaction

The results obtained for samples prepared up to this time appeared tobecome fully crosslinked after about 7 days at elevated humidity andwithin 18 weeks under ambient, packaged storage conditions. Based onthese results it is apparent that it may be even more desirable tocreate a crosslinked structure without exposure to high humidity or torequire extended storage at ambient conditions. This objective could bemet if a catalyst for the crosslinking reaction could be identifiedwhich could be added just prior to fabrication into the final structure.The catalyst should accelerate the crosslinking reaction so thatcrosslinking of the structure occurs under ambient storage conditionswithin the normal lag time between manufacturing and usage.

Resin pellets obtained from the second factorial experiment on theZSK-30 PEO (POLYOX 205 reactively grafted with 7.3 weight percent Z6030)was coated with various levels of stearic acid by shaking the pelletsand the stearic acid powder together in a plastic bag. Since there wasnot enough of any single sample to conduct the catalyst study, acomposite sample was prepared by blending Samples 1-9 into a single“average” composition. Addition levels of stearic acid were 0, 0.1, 0.2,0.4, 0.6 and 0.8 weight percent. The blends with stearic acid wereprepared within four days of the reactive extrusion to minimizecrosslinking during storage. Each blend was cast into a film using theHAAKE extruder under the conditions described above.

Film Observations And Gel Fraction

The results are show in the Table 18 below.

TABLE 18 Stearic Film Casting Gel Fraction after 1 Acid LevelObservations day of ambient storage 0 Smooth, thin film 60% 0.1 Smooth,thin film 55% 0.2 Smooth, thin film, slight 47% torque increase 0.4Smooth film, slightly thicker, 81% higher torque 0.8 Rough film,thicker, 96% higher torque

The results above are somewhat obscured by the fact that the resin withno stearic acid added had a high gel fraction. (The gel fraction testingof Samples 1-9, which were combined for this study, was completed afterthe catalyst study). Nevertheless, the results indicate that addition ofstearic acid at a level of at least 0.4%, is effective at increasing thegel fraction after just one day of storage under ambient conditions.However, the results also indicate that addition of excessive stearicacid causes difficulty in fabricating the resin into final form,presumably from premature crosslinking inside the extruder.

EXAMPLE 12

The resin from Example 6 (sample 6-1) was used to prepare monofilamentson a pilot-scale fiber spinning line. The spinning line consisted of two¾ inch diameter 24:1 l:d (length:diameter) extruders with three heatingzones which feed into a spin pump, through a ¾ Koch SMX static mixerunit and then into a spinpack, from which the monocomponent fibers werespun. The spinpack had 15 holes of 0.5 mm diameter.

The monofilament fibers were processed using the one extruder with atemperature profile of 170° C., 175° C., 180° C., 180° C., 180° C., 185°C., 185° C., for zones 1 through 3, melt pump, mixer and spinpack. Thefibers were quenched at ˜26° C. and collected in a freefall state(without draw down by a draw roll). The fibers were collected onto aspindle for testing.

Fiber samples were exposed to humid air (37° C. and 80% relativehumidity) for one week and then tested for gel fraction according to thetest method previously described. The fibers were found to have a gelfraction of 57% and absorbed 21 grams of water per gram of fiber.

The fibers displayed significant swelling in water. Fibers were cut to25 mm in length and found to have a diameter of 0.38 mm in the drystate. After 30 minutes of immersion in water at room temperature, thefibers swelled to a length of 57 mm and the diameter increased to 2.0mm. The dimensional changes observed were a length increase of 2.25times the original length and an increase in diameter of 5.2 times thediameter of the dry fiber.

The series of foregoing Examples indicates that the material of thepresent invention has a unique combination of attributes: goodabsorbency for water, urine, and menses along with the capability tofabricate a wide range of structures using thermal processing. Theability to generate structures in a latent form (uncrosslinked) via meltprocessing coupled with a facile method to induce crosslinking into anabsorbent material is very rare.

The absorbency properties of this new material are at an intermediatelevel between polyacrylate superabsorbents and cellulose pulp as shownin Table 19 below.

TABLE 19 Comparative Cross- Polyacrylate Cellu- Absorbent linked super-lose Properties PEO absorbent pulp Free swell absorbency 12-25 g/g 26-39g/g 3-6 g/g Absorbency under 0.5 psi load 8-14 g/g 20-30 g/g 2 g/g

Another beneficial property provided by using PEO as a starting polymeris a low glass transition temperature. This attribute is particularlybeneficial for personal care or medical products because the structuresmade from this material are soft and flexible—much like polyethylene orpolypropylene which is commonly used to fabricate products in thesemarkets. Plastic-like mechanical and fabrication properties along withgood absorbency make this material highly unique. Some potential uses ofthe present invention are described below.

It is at the level of fabricated structures that the thermoplasticprocessability of the present invention opens up a wide range ofpotential structures. The present application describes simple filmswith good dry properties and high absorbency. When these films areplaced in contact with fluid, they swell significantly (by a factor ofabout three times the original cross-machine direction). In addition,the films upon absorbing fluid are transformed from a plastic film to aneven softer more compliant and unexpectedly elastomeric material.

Film applications are not limited to monolayer films. Also anticipatedare multi-layer films (coextruded or microlayers). Films may be filledwith particulate, such as polyacrylate superabsorbent particles, ormineral fillers, such as clay. The forms described may also be appliedto blends composed of alkoxysilane-grafted PEO with other polymers.Also, a wide variety of laminated structures are possible. For example,films may be laminated with nonwoven structures, such as meltblown orspunbond. Laminates are possible with tissue webs or woven fabrics.Specifically, a layer of film in accordance with the present inventioncan be laminated between two nonwoven layers, such as sheets of tissue.Fibers in accordance with the present invention may be laminated withother structures or with other fibers made from the same or differentmaterial, such as pulp. Fibers can be laminated with films of the sameor different material. Because the alkoxysilane-grafted PEO has a ratherlow melting point, the laminates may be fabricated by melt extrusiononto the other component or by applying pressure to both components asthey passes through heated nips.

Because of the thermal processability of alkoxysilane-grafted PEO, thepresent invention may be used for fabricating foam structures. Thermallyprocessed foam technology is widely practiced with polyethylene byutilizing chemical and physical blowing agents. Alkoxysilane-grafted PEOhas properties similar to polyethylene so it is contemplated that theuse of chemical blowing agents will also produce foam structures.However, unlike polyethylene foams, the foams made fromalkoxysilane-grafted PEO should be highly absorbent. Extension of thefoam technology to produce net-like structures is also anticipated.Laminates can also be formed from foam structures. Specifically, foamsin accordance with the present invention can be laminated with films ofthe same or different materials.

It is expected that fibrous structures can be fabricated with thealkoxysilane-grafted PEO. Such fibrous structures include melt blown andspunbond nonwovens, as well as bicomponent fibers and structures madefrom them. Filaments that swell and become elastomeric when contactedwith fluid are possible.

The compositions of the present invention can also function as anadhesive. For example, a first material may be adhered to a secondmaterial by interposing between the first and second materials and incontact therewith a melt processed poly(ethylene oxide) having graftpolymerized thereto an organic moiety including a trialkoxy silanefunctional group or a moiety that reacts with water to form a silanolgroup at an elevated temperature, and permitting the melt processedmaterial to cool to ambient temperature.

With this wide range of potential structures, and the product uses foralkoxysilane-grafted PEO are enormous. Articles that are made byinjection molding, blow molding, or thermoforming can also be made fromalkoxysilane-grafted PEO. Within the personal care market, the presentinvention is well-suited for a thin, elastomeric film for urine ormenses absorption. Alkoxysilane-grafted PEO may also be used as a wounddressing to absorb wound exudate. Laminates prepared from this materialmay also be used as absorbent bed pads.

The change in properties upon contact with fluid from a plastic to anelastomeric material indicates a relaxation process within the structurethat may be utilized for controlled release of beneficial agents.Another application is an implantable material to prevent surgicaladhesions. The anti-adhesion properties of PEO are well documented. Thisproperty of PEO combined with the capability of alkoxysilane-grafted PEOto form an insoluble gel structure when exposed to fluid may provide thecombination of properties to solve the significant problem of surgicaladhesions.

The properties of alkoxysilane-grafted PEO in the gel state have notbeen extensively investigated. However, because it does form an easilyprocessable fluid-filled gel it may be used as a conductive material fordetection electrodes or as a conducting medium for polymer batteries. Inaddition, there is good potential that alkoxysilane-grafted PEO mayfunction as an effective chromatographic medium in the gel state.

The present invention has been illustrated in great detail by the abovespecific Examples. It is to be understood that these Examples areillustrative embodiments and that this invention is not to be limited byany of the Examples or details in the Description. Those skilled in theart will recognize that the present invention is capable of manymodifications and variations without departing from the scope of theinvention. Accordingly, the Detailed Description and Examples are meantto be illustrative and are not meant to limit in any manner the scope ofthe invention as set forth in the following claims. Rather, the claimsappended hereto are to be construed broadly within the scope and spiritof the invention.

What is claimed is:
 1. A method comprising: combining poly(ethyleneoxide), an initiator and an organic monomer capable of graftpolymerization with said poly(ethylene oxide), said organic monomerincluding a trialkoxy silane functional group or a moiety that reactswith water to form a silanol group; and subjecting the combination ofpoly(ethylene oxide), the initiator and organic monomer to reactiveextrusion conditions sufficient to graft polymerize the organic monomeronto the poly(ethylene oxide).
 2. The method of claim 1, wherein theinitiator is a free radical initiator.
 3. The method of claim 1, whereinthe organic monomer is selected from methacryloxypropyl trimethoxysilane, methacryloxyethyl trimethoxy silane, methacryloxypropyltriethoxy silane, methacryloxypropyl tripropoxy silane,acryloxypropylmethyl dimethoxy silane, 3-acryloxypropyl trimethoxysilane, 3-methacryloxypropylmethyl diethoxy silane,3-methacryloxypropylmethyl dimethoxy silane, and 3-methacryloxypropyltris(methoxyethoxy) silane.
 4. The method of claim 1, wherein theconditions sufficient to graft polymerize the organic monomer onto thepoly(ethylene oxide) comprise heating the poly(ethylene oxide), theorganic monomer and the free radical initiator to a temperature withinthe range of the melting point of the poly(ethylene oxide) to thedecomposition temperature of the polyfethylene oxide).
 5. The method ofclaim 1, wherein the conditions sufficient to graft polymerize theorganic monomer onto the poly(ethylene oxide) comprise heating thepoly(ethylene oxide), the organic monomer and the free radical initiatorto a temperature within the range of about 120° C. to about 220° C. 6.The method of claim 1, wherein the poly(ethylene oxide) has an initialapproximate molecular weight ranging from about 10,000 grams per mole toabout 8,000,000 grams per mole as determined by rheologicalmeasurements.
 7. The method of claim 1, wherein the poly(ethylene oxide)has an initial approximate molecular weight ranging from about 300,000grams per mole to about 8,000,000 grams per mole as determined byrheological measurements.
 8. The method of claim 1, wherein thepoly(ethylene oxide) has an initial approximate molecular weight rangingfrom about 50,000 grams per mole to about 400,000 grams per mole asdetermined by rheological measurements.
 9. The method of claim 1,wherein the poly(ethylene oxide) has an initial approximate molecularweight ranging from about 50,000 grams per mole to about 200,000 gramsper mole as determined by rheological measurements.
 10. The method ofclaim 1, wherein the organic monomer is added within the range of about0.1 to about 20 weight percent relative to the weight of thepoly(ethylene oxide).
 11. The method of claim 1, wherein the organicmonomer is added within the range of about 0.5 to about 10 weightpercent relative to the weight of the poly(ethylene oxide).
 12. Themethod of claim 1, wherein the organic monomer is added within the rangeof about 1.5 to about 5.5 weight percent relative to the weight of thepoly(ethylene oxide).
 13. The method of claim 1, wherein the initiatoris added within the range of about 0.05 to about 0.75 weight percentrelative to the weight of the poly(ethylene oxide).
 14. The method ofclaim 1, wherein the initiator is added within the range of about 0.10to about 0.35 weight percent relative to the weight of the poly(ethyleneoxide).
 15. The method of claim 1, wherein the initiator is added withinthe range of about 0.15 to about 0.25 weight percent relative to theweight of the poly(ethylene oxide).
 16. A modified poly(ethylene oxide)produced by the method of claim
 1. 17. A method comprising: adding to areaction extrusion vessel poly(ethylene oxide), 0.1 to about 20 weightpercent relative to the weight of the poly(ethylene oxide) of an organicmonomer capable of graft polymerization with said poly(ethylene oxide),said organic monomer including a trialkoxy silane functional group or amoiety that reacts with water to form a silanol group, and a freeradical initiator; mixing the poly(ethylene oxide), the organic monomerand the free radical initiator; and reactive extruding the mixture toabove the melting point of the poly(ethylene oxide) to form a graftedpoly(ethylene oxide).
 18. A method comprising: adding to an extruder apoly(ethylene oxide), 0.1 to about 20 weight percent of an organicmonomer capable of graft polymerization with said poly(ethylene oxide),said monomer including a trialkoxy silane functional group or a moietythat reacts with water to form a silanol group, and a free radicalinitiator; and mixing and heating the poly(ethylene oxide), the organicmonomer and the free radical initiator while extruding in order to graftthe organic monomer onto the poly(ethylene oxide).